Study of rydberg atoms using spectral profiles in sum frequency generation

Abstract

Spectral profilesI 3(ω3) in sum frequency generation (SFG) ω3=2ω1+ω2 in gases using two dyelasers ω1, ω2 are analyzed to study atomic Rydberg states. They are measured by locking laser 1 to a two-photon transition 2ω1=Ω ge and shifting laser 2 across Rydberg transitions Ω en (g=ground-,e=excited-,n=Rydberg state). From optically thin line wings (|ω3−Ω gn |»Γ gn =homogeneous line width) dipole moment products μ en μ ng may be derived, from optically thick line cores (|ω3−Ω gn |≦Γ gn ) oscillator strengths ≈|μ ng |2. Both quantities yield the individual dipole moments μ en , μ ng and phase information of the wavefunctions involved. Explicit evaluation procedures based on the small signal theory of the SFG process are presented and discussed. The potentialities of the method are demonstrated at the SFG spectrum of Cadmium I in the near Vacuum-UV involving Rydberg states5snp in the rangen=12−28.